In connection with the automatic machining of parts, it is well-known to utilize programmed machining operations in conjunction with automatic, programmed loading and unloading facilities. Typically, however, automatic loading and unloading equipment tends to be of a highly customized nature and therefore very expensive to manufacture and install. As a result automatic loading and unloading equipment tends to be limited to relatively larger and more costly machining equipment, in which the cost of the loading/unloading facilities can readily be absorbed in the overall cost of the equipment.
The present invention deals with the provision of automatic loading/unloading equipment intended especially for relatively small, relatively low-cost machining equipment, such as a small, high speed automatic lathe.
In part, the invention is directed to the provision of a novel, highly simplified and highly universal form of workpiece loading mechanism for a small automatic lathe or the like. A particular feature of the invention resides in its highly universal construction, such that it may be utilized in large measure in the handling of a great variety of parts for a small automatic lathe. Accordingly, because a great deal of the loader mechanism is of a standardized construction, the cost of installing the loader may be kept to a minimum in keeping with the nature of the parts being manufactured and the equipment upon which the work is being performed.
Pursuant to one aspect of the invention, a novel and improved vertical positioning mechanism is provided which includes a relatively simplified yet extremely effective universal mounting bracket arrangement, for mounting of the vertical positioning mechanism in an effective working position, given the nature of the workpiece being handled. To advantage, the apparatus includes a generally L-shaped bracket, which is adjustably mounted above the spindle housing of an automatic lathe or the like, positioned for limited fore and aft adjustment in the direction of the spindle axis for proper positioning of the loading mechanism in front of the spindle and chuck. An upwardly extending portion of the L-shaped bracket adjustably mounts a positioning mechanism, including a workpiece holding cradle and vertical guide means for raising and lowering the cradle. The mechanism is driven by an actuator, provided with adjustable stop means for limiting the length of the stroke. By adjustably vertically positioning the mechanism on the L-shaped bracket, and adjustably limiting the stroke of the actuator, the vertical movement of the workpiece carrying cradle may be precisely adjusted at upper and lower limit positions.
Pursuant to the invention, the workpiece positioning mechanism generally described above can be substantially universally applied to the handling of a wide variety of sizes and shapes of workpieces such that, even though the specific loading requirements are highly individualized and highly customized, the loading apparatus of the invention may nevertheless be standardized to a fairly high degree, so that the part loading equipment may be made available to the machine users on a cost-effective basis.
With the apparatus of the invention, the main workpiece positioning mechanism is retracted during machining operations, during which time a single workpiece is loaded into a movable cradle block. Upon completion of a machining operation, the finished part is ejected from the work-holding chuck, and the part loader is actuated to bring the new workpiece into precise alignment with the chuck. At this juncture, a second actuator is operated to drive the workpiece out of its delivery cradle and into the gripping chuck. Because various parts may vary greatly in overall length, the apparatus of the invention contemplates and accommodates a variety of mechanism for injecting the workpiece from the delivery cradle into the gripping chuck. One of the significant advantages of the structure of the invention, in this respect, is that the basic workpiece positioning mechanism is sufficiently universal in its design to accommodate a variety of simple and inexpensive part injector mechanisms which may be carried by or mounted independently of the delivery mechanism.
In one advantageous form of the invention, useful for very short parts, a simple injector lever mechanism is carried by the workpiece positioning apparatus. When the workpiece is delivered into alignment with the gripping chuck, the injector lever is also in alignment with an actuator device, mounted on the main universal bracket. When the mechanisms are thus aligned, the injector actuator is energized to cause the part to be delivered into the gripping chuck.
In another advantageous form of the invention, useful for parts of somewhat greater length, the injector actuator may be carried directly on the workpiece positioning mechanism.
For still longer parts, the part injector mechanism may be mounted in fixed relation on the universal bracket and provided with an elongated operating rod, which extends over the top of the workpiece, when the latter is aligned with the gripping chuck, and engages the part from its outboard end. The actuator is then retracted to cause the workpiece to be injected into the gripping chuck from the delivery cradle.
In accordance with another aspect of the invention, novel and advantageous facilities are provided for the feeding and ejection of highly elongated workpieces, so that both the part injection and ejection operations are carried out reliably, but at a relatively high rate of speed, in keeping with the demands of a high speed machining operation. To this end, one of the features of the invention relates to the provision of a new and advantageous construction of saw tooth-type feeder, especially for feeding elongated workpieces one-at-a-time to the loader mechanism, while maintaining the workpieces under effective control. The new mechanism uses an advantageous form of actuating arrangement for a saw tooth-type feeder, providing a reliable and rugged mechanism at minimum cost.
In accordance with another aspect of the invention, novel and unique arrangements are provided, for use in a draw tube collet chuck gripping mechanism, for ejection of the workpiece from its gripping collet. In a collet chuck gripping arrangement, it is typical to provide an elongated rearwardly extending draw tube engaged at the rear of the spindle for drawing the collet chuck into a tapered socket and thereby causing gripping pressure to be exerted on the workpiece. In the apparatus of the invention, novel arrangements for part ejection are incorporated within the hollow draw tube in a highly unique and advantageous manner. In one particularly advantageous form, the draw tube constitutes an integral part of a fluid actuating cylinder, which serves to eject a finished workpiece from the collet at the end of a machining operation.
For a more complete understanding of the above and other features and advantages of the invention, reference should be made to the following detailed description of preferred embodiments of the invention, and to the accompanying drawings.